Smoking cessation worsens Type II diabetes

For many years, the government told you the single best thing you could do for your health was to quit smoking. But rarely do simple-minded government recommendations reveal the whole truth. In fact, a new study shows Type II diabetics who quit smoking worsened their blood sugar control.

Now–it’s certainly true–cutting back on smoking is a positive step.

For example, I published research about smoking in the late 1980s in the American Journal of Public Health with a team of colleagues from the National Cancer Institute. We used data from the U.S. National Health and Nutrition Examination Survey.

Results showed that people who smoked cigars and pipes only, and people smoked less than half a pack per day of cigarettes had better overall health profiles compared to non-smokers. Furthermore, cigar and pipe smokers/light cigarette smokers also had healthier body weights.

For the new study, researchers published their explosive findings about diabetic smokers in Lancet Diabetes & Endocrinology. The data came from The Health Improvement Network (THIN) study, which includes electronic medical records from over 35 million patients in 546 primary care practices.

Specifically, the study looked at blood levels of Hemoglobin A1C (HbA1C). This reading provides a measurement of the amount of sugar linked to hemoglobin in red blood cells (glycosylated hemoglobin). HbA1C provides an average reading of blood sugar levels over time, since blood sugar itself fluctuates. It is the standard for assessing blood sugar control.

Lowering HbA1C helps prevent the eye, heart, kidney, nerve and vascular complications of Type II diabetes. It also helps prevent mortality. Doctors closely monitor this number in patients with diabetes or pre-diabetes.

The study included 10,692 Type II diabetic patients who smoked. Nearly a third of these patients subsequently quit smoking for at least one year. In these quitters, HbA1C levels increased from an average 7.7 to 7.9–which represented a 3 percent increase.

That amount may not seem like much.

But doctors do everything they can–and try to make their patients do everything they can–to keep HbA1C levels below 7.5. With an average of 7.7 HbA1C in these diabetic patients, the goal was to lower it by 0.2 points to 7.5. Instead, quitting smoking had the opposite effect. It raised HbA1C by 0.2 points in the wrong direction.

Treating or controlling Type II diabetes is a lot like football. It’s a game of yards and inches.

Gaining the yards involves major changes in diet like cutting out sugars and carbs, losing excess body weight, increasing healthy physical activity, as well as taking a safe and effective drug like Metformin when necessary. (Metformin derives originally from the ancient European herbal remedy, French lilac.)

The game of inches comes down to fighting for every 0.1 point of HbA1C. Going the wrong direction by 0.2 points when you are on the goal line is like losing yards when you run a last-ditch play on fourth down on the one-yard line and end up behind the line of scrimmage.

Of course, the Type II diabetic patients who quit smoking also gained an average of 11 lbs for their trouble. And this makes sense, since men and women who quit smoking often experience intense food cravings. Especially for sweets. But there are also direct metabolic effects behind weight gain after quitting smoking that have nothing to do with diet itself.

In any case, the weight gain didn’t cause the spike in HbA1C. The researchers actually controlled the data for weight gain. And according to their analysis, the increase in HbA1C was above and beyond the effects of weight gain.

Of course, despite these findings, researchers and editorialists quickly backtracked and continued to recommend complete cessation, immediately, for anyone and everyone. Including Type II diabetics struggling to cut sweets, lose weight, and lower HbA1C levels. Amazingly, they even worked in a recommendation for diabetics to keep taking toxic and ineffective statin drugs.

Lastly, they even “dropped back to punt,” suggesting genetics may somehow explain these findings. Perhaps these patients somehow have a “faulty” gene that makes their blood sugar rise after quitting smoking. Ah, yes. Blame everything on the old mysterious and elusive “faulty” gene when your findings don’t fit into your politically correct (but clearly flawed) theory and practice.

Here’s what troubles me the most…

Nobody simply counsels patients anymore to cut back smoking to half a pack per day or less.

Cutting back to that amount could help lower cancer and heart disease risks. Plus, the patients would maintain a healthier body weight, as our U.S. NHANES data from the 1980s showed. It would probably also thwart this uptick in HbA1C in diabetics.

Many, if not most, people who completely quit smoking start again at some point. So, for a lot of people, cutting back would be a more realistic goal than trying to quit “cold turkey.” And it may even prove a healthier approach overall in terms of blood sugar control, as this new study suggests. Plus–previous research already showed quitting smoking increases the risk and worsens the symptoms of Parkinson’s disease as well.

Bottom line?

The best health advice is the kind that that people can actually follow.

And that actually follows the science.


“The association between smoking cessation and glycaemic control in patients with type 2 diabetes: a THIN database cohort study,” The Lancet Diabetes & Endocrinology ( (4/29/2015)